text:
What is a representative electricity consumption for a medium-/long-haul airliner when stationary?
I am looking into the typical energy usage of a passenger aircraft when stationary. There are two options:

Using the APU
Connection to any ground equipment such as a GPU

I have some data to analyse to see whether an aircraft uses the APU. The data basically shows signals for ground power usage, and I assume that the aircraft uses the APU when no signals are sent. However, this does not always hold. Sometimes you see patterns with a bit of usage and then nothing. The amount of electricity also differs a lot per flight and aircraft. Can anyone tell me more about the typical electricity demand of a commercial, passenger flight?
Are there typical patterns? Does the APU have priority over ground power when both can deliver electricity (so when ground power is connected and the APU is switched on, where does the aircraft take its power from)?

Welcome to aviation.stackexchange.com! What typical aircraft are you looking at? A business jet, a turboprop commuter, a medium range passenger aircraft, a long haul passenger aircraft, a long haul cargo aircraft? The number will vary greatly amongst those

a typical commercial passenger flight that can be either medium-range or long-haul. I'm not interested in business jets or cargo flights.

out of interest, why do you want to know? Providing a bit of background to the question may help people to tailor their answers.

I think there's an assumption here that the APU only generates power. The APU also provides high-pressure bleed air, used to air condition and pressurize (in flight) the cabin. This is true on all large planes except the 787, which uses electrical compressors from APU or ground power. The question is hard to answer. Does "energy" = electricity? What data do you have?

I reworded the title in order to fit a little better the comments. If it's not the right thing, revert?

@KennSebesta - some of the OP's wording can sound as if they are asking about total power consumption, and it seems that most people are interpreting the question this way. But I suspect the OP is only asking about what if any power differences could be detectable via some unspecified data they are looking at, so that they can determine from the data where the power is coming from. I think this may be what they are looking for based on their statement, "I have some data to analyse to see whether an aircraft uses the APU. The data (shows such and such). However, this does not always hold."

This is from memory from a few years ago. When I was working ground for 767 aircraft the ground power units were typically supplying around 50amps 115v(3phase as I recall) although they would, of course, fluctuate with the number of systems turned on, belly-cargo lights, main-deck lights, or if a cargo door or conveyor was in motion.
There is a switch in the cockpit to manually select APU or GPU electricity, which is usually used after starting the APU or an engine just before disconnecting from the GPU. Most modern aircraft will automatically switch to ground power when it is connected and a cockpit light indicates the source of power.

As you provided no information on the type of aircraft I will be vague in most parts.  A Boeing 747 will take up some more power than a small business-jet - though the systems internally can mostly compared to each other. And it also depends on the exact situation the plane if in - depending on the number and type of equipment powerd on.
First thing to understand there are two seperate power systems on bord - AC and DC. Both normally are split up in several (normally) isolated buses.
DC (quite often nominally 28V) is either supplied by onboard batteries or transformer-rectifiers (like the normalal DC-power bricks at home) from the AC sources.
AC (110V/400Hz) has normally three main power sources - main engine generators, apu and ground power. What system you draw power from will be decided by the pilots and is normally exclusive - though it was done in earlier aircraft, today planes do not syncronize their AC busses so also the different AC-busses will have distinct power sources. So only one of them...
As a backup for a failed engine generator you can either tie both ac-busses together or bring the APU online on the failed bus. (or turned off engine when doing single-engine taxi)
Ground power is nearly always powering both AC busses at the same time, so you don't mix it with other power sources.


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Why are lat-lon coordinates written at parking bays in civil airports?
Why are coordinates marked at parking bays at civil airports?

If you are referring to GPS coordinates shown at the gates, as in this image:

Source: ADB Safegate
the reason is: to allow the pilots to properly prime their inertial navigation system with a known location before the flight begins.

With that much precision given, I am curious if that is the latlong position of the sign, or of the approximate position a cockpit would be when stopped at that stand. When the position is that of the sign, are there procedures to convert that to the cockpit position?

Looking at google maps it's probably the cockpit position

@Ian I suspect there'd be some variation in that depending on the model of the plane, but it'd probably need a few more decimal places to be accurate enough for that to matter?

Those are not "GPS coordinates", they were used there well before GPS was invented. The OP's term "coordinates" is entirely sufficient.

@mins There are aircraft without GPS. Even with FMS but without GPS (but becoming rarer with every year). The INS needs a starting point and then tracks the movement. The drift can be corrected using DME triangulation, but for the starting point the coordinates written there are much more accurate than DME. The FMS certainly can have the posittion in the database. Or it might not.

@mins OK, the self alignment is possible, but some information is still needed. E.g. the longitude when last shut down.

@mins I did not invent this myself. And the comments under your answer also confirm that longitude cannot be determined automatically. https://www.skybrary.aero/index.php/Inertial_Reference_System_(IRS)#Alignment

Let us continue this discussion in chat.

@ontrack The sign was made and to provide the location of the aircraft parked at the gate for the purpose of calibrating the navigation system. I doubt that anyone has ever measured the Lat/Long of the location of the sign.

@VladimirF This is a major airport (Calgary International, Alberta, according to the provided coordinates) - I suspect it's going to be mostly bigger professional airlines landing here, which would probably all be equipped with GPS.  Smaller private planes without such equipment probably don't land here often.

@DarrelHoffman Actually, even old small planes do have GPS, it is easy to buy one. But old big airplanes may be without one. It is less easy to integrate one ex post into the system.

@DarrelHoffman One second of latitude  is about 30 m, so the co-ordinates given above have a precision of around 30 cm for latitude and an even smaller distance for longitude. So there are more than enough significant digits there to distinguish sign versus cockpit location and locations in between.

These checkpoint coordinates are used to verify the current location of the aircraft for navigation purposes. The coordinates can be used to check, input or calibrate the navigation system's current location.
It can be used to input or calibrate the aircraft's Inertial Reference System (IRS) during initial alignment by providing a precise Latitude/Longitude location the pilot can input into the system when the aircraft is powered up.
The IRS uses 3 laser gyros to sense the forces created when the aircraft moves from this starting position, updating the IRS's position accordingly.
As you'd expect, due to drift, the IRS position will not remain accurate after crossing the Pacific Ocean. Once within range of ground-based navigation facilities, the aircraft's location is updated by the Flight Management System ("FMS" - the airplane's navigation computer) utilizing data from these facilities, such as VORs (many of which provide distance information via DME) which the computer uses to triangulate a position.
Information from ground-based navigation facilities is not available until airborne, so you need the Lat/Long gate location for INS initial alignment at the gate (especially if you were flying in 1990 or are currently flying an aircraft from the 1980s or early 1990s that is not yet updated with GPS capabilities).
The Flight Management System (FMS) navigation database of a modern airplane will typically contain the Lat/Long coordinates for various gate locations at major airports.
GPS (Global Positioning System) satellite position information can also be used by the FMS to update the aircraft's position.
On modern aircraft GPS provides an accurate Latitude Longitude position to your navigation system no matter where you are (including sitting at the gate).
While these Lat/Longs at the gate are likely a bit of a holdover from the 1980s/1990s when you needed a Lat/Long position for your INS and could not get it from GPS, these coordinates at the gate are still valuable, giving you the ability to check the accuracy of your indicated GPS location or verify the gate position shown in the FMS navigation database (in addition to giving your IRS a current location for initial alignment).
These gate Lat/Long coordinates are also indicated on some Jeppesen airport diagram charts which show zoomed in gate details.
I just did a search to see if someone already has explained the IRS system here, and found an extremely thorough and detailed description.
Check it out:
Why are there two IRS switches on the 737NG?

Mentour Pilot covered IRS (from 07 min 44 secs) and the other kinds of navigation in great detail in How do pilots actually navigate the skies?. The approx. 10 minutes required for alignment of IRS after aircraft startup at the airport is explained from 14 min 25 secs. It didn't include anything about the signs (except perhaps hinted by "input position").

You should also mention that DME/DME systems may not be able to provide a fix to the INS until airborne, so they need a precise fix at startup time. Even GPS systems may need several minutes, depending on how long they were shut down (or if they don’t cache ephemera).

Doesn't the FMS know the position of each gate already?

Even with BRNAV (Like INS only with RNP 5) you can do a usual RNAV SID and STAR if it does not require PRNAV or RNP1 or equivalent.

@mins If you have a FMS with a database of them, then sure. If you don't, you can use the sign.

Reliance on the GPS network seems like a slight problem. Has an aeroplane ever been brought down by GPS spoofing?

@StephenS Thanks for the suggestions, I have updated the answer with them.  Let me know if the answer has room for additional improvements or corrections.
Vladimir and user253751's comments are about a section I removed where I went on a tangent about GPS and how your navigation ability is reduced if you are not GPS-equipped. I decided my GPS comments were not relevant to directly answering the question in a concise clear way.

user253751, it seems unlikely since the GPS will immediately alert you if you lose signal, in which case you'd revert back to using ground-based nav facilities like VOR/LOC/ILS etc.  GPS is based upon a system of 24 satellites (minimum) [plus 2 more for WAAS in the US], but you only need 4 to get a good position.
While on a GPS approach you need to have 5 to provide RAIM (receiver autonomous integrity monitoring).  If you lose one of the 5 you will get an alert that RAIM has been lost. (My GA flight instruction experience is mostly with Garmin G1000, 430 and 530 units)

@JetCityMatt because of how GPS works, a single transmitter sending the "right" false data is all that is needed to trick a receiver. Something like a software defined radio is capable of pretending to be all 12+ satellites that would be expected to be in view.

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Why are tip tanks used?
The answer to this question identifies the "pods" as tip tanks.
Why do manufacturers sometimes use tip tanks rather than wing tanks? Or is it only when the wing isn't large enough to hold the desired fuel quantity? It seems like filling the wing with fuel first would be more efficient due to less drag.

Do you have any evidence that this is a feature seen on recently developed aircraft?

Tip tanks are only used when the wing volume is not sufficient to carry the needed fuel. They can mostly be found on the early jets which had thin wings for a higher Mach number of drag rise onset and very thirsty engines. They offer two advantages over conventional external tanks:

Their wing tip location allows the highest wing bending relief for a given fuel mass.
They widen the wing by their diameter, so reducing induced drag a bit.

Later designs used the area rule to shape the tip tanks, so they could help to reduce wave drag a bit, especially on designs which predated the knowledge of efficient transsonic shaping.
On fighter aircraft, tip tanks should be jettisoned with the start of air combat because their high roll inertia contribution puts the aircraft at a clear disadvantage.

The XF-104, the prototype of the Lockheed Starfighter. Where else would it allow to store all the fuel?

For small planes, putting fuel in tip tanks lets you add extra capacity without having to re-engineer the fuel cells inside the wing or the shape of the wing itself. It also lets you offer the plane for sale with or without the tip tanks so your customers can tailor the available tankage to best match their intended use model for the plane.
It also means you can add tankage without having to put fuel in a fuselage tank near the passenger compartment, thereby reducing fire hazards in a crash and improving things like load distribution issues on the main spar.

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How does ATC direct aircraft on ground from the parking to the runway?
For medium size airports, ATC will direct aircraft with a single message like this "Taxi to runway 29 via Papa, Sierra".
I was wondering if it was the same thing for bigger airports (like international airports) which have a lot of taxiways.
I know that if the pilots are not very familiar with the airport, they can ask for controller guidance. But does the ATC can give all the taxiways points like for medium size airports?
Thank you

This question begs for a "Kennedy Steve" answer: https://www.youtube.com/playlist?list=PL_ei74pHoe4qfmuVrmQYP1LLJL25paqnr Note: Kennedy Steve was a ground controller at JFK who achieved some YouTube fame due to funny radio transmissions.

Yes, it's the same. An airport consists of one or several runways, one or several parking areas (aprons) and a number of taxiways connecting them. All runways and taxiways are uniquely named.
When taxiing around the airport - be it from runway to parking, or vice versa, or between parking areas, hangars etc. - ATC instructs the pilot of the exact route to follow by specifying the taxiway names in order. ATC can also instruct the pilot to stop and wait at a certain position, or to follow or give way to specific other aircraft. Some airports, in addition to named taxiways, have named holding points around the airport which can be used to specify where the aircraft should stop and await further instructions.
Pilots who are not familiar with the airport will have no problem following instructions, since they all have a ground chart (essentially a street map) of the airport layout, with all the taxiway and runway names.

Example of aerodrome chart - Copenhagen Airport, reproduced from AIP Denmark
Some modern airliners even have a moving map which shows the aircraft GPS position directly on a digital airport map in the cockpit. In addition, signs are posted at all taxiway and runway intersections, showing the name of the current and any adjacent taxiways and runways.

Taxiway signs
In extreme cases, ATC can make use of turn-by-turn instructions (progressive taxi), but that is very rarely needed. Follow-me/marshall vehicles are also available, but those are usually not to help the pilot find the way, but rather to provide an extra set of eyes when taxiing very big aircraft, to ensure they stay on the pavement during a narrow turn/tight gap etc.

What happens in the flight deck at an airport with a complex taxiway system (like NY JFK, which has many multiple parallel taxiways and numerous wrong-turn traps) is the pilot taking the clearance will (should) write it down like a flight plan clearance before reading it back (it's a good idea to write down any clearance with more than 3 elements in it).
Before you start to taxi, a crew with good Crew Resource Management practices will than review the clearance and plot the route on the airport chart together, and mutually agree that the route they are taking is the route in their taxi clearance.  Then, if there is any doubt on the way to go at any point, call it in to confirm.  Such airports have ground radar and know where everybody is on the taxiways, so in the end you can just call and ask directly which way to go if it comes to that.

Taxi schemes vary with the airport, and also with the prevailing conditions.  Some airports may issue a taxi clearance to a runway with intervening taxiways, while others may issue a taxi clearance to a holding point, and then issue another clearance as the aircraft approaches that point.  Some locations use standard taxi routings with comprehensive airport information that each crew member must be familiar with. Others simplify.
Incheon, for example uses green taxiway lights and the crew will simply be given the initial taxi instruction, followed with "follow the green."  Green lights illuminate in the taxiway progressively to guide the pilot, and stop bars or hold short indications will be given otherwise, with verbal direction as well.
Some international airports can be complex, and confusing.


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How can I find places to store/land a private airplane?
Say I'm the proud new owner of a Cessna 172.
To celebrate, I want to fly my family from Texas to Orlando Florida for a weekend visit.
Local takeoff is easy enough. I live close by, and I know the locals so I can "borrow" a runway.
However, how do I coordinate the landing in Orlando? I know commercial options are available like the Orlando International Airport, but that seems... expensive.
Even if I paid to land the Cessna (which I have no idea of the red tape involved with this), I'd still have to find somewhere to "park" to plane for my weekend trip.
However, looking at other options in the area I see several flight schools, and even some "private owned" airports with operational runways.
Which brings me to my question: if the pilot of a small aircraft wants to land in place far yonder, what's the best way to plan for this?
Is it common practice to call all the "small guys" in the area first and see if they're willing to work with your flight schedule?
If they gave you the go-ahead to land and store your aircraft in their facilities, is there any paperwork you should sign to protect your aircraft in the case of theft/vandalism?
What if the commercial airport is the only viable "runway" you see close to your target destination? What red tape is involved with landing/storing a small aircraft on commercial landing strips?

I wonder the same, but within the European Union.

You are putting way too much thought into this.  Basically, you pick an airport somewhere near Orlando, fly to it, land, and taxi to the ramp to park.  At small airports the parking area is generally obvious.  At large airports you may need to do a few minutes of research before you depart.  In any case, fly there, land, park, Uber to where you need to ho, come back, pay the parking fee (if any), and then fly home.  GA airports in the US don't have landing fees that I am aware of...or have ever paid, anyway.

The first step should be to obtain your PPL (pilot's licence).  If you still don't know the answer to this question after you do that, you're probably going to get a lot of phone calls every time you fly.

Are you familiar with the term "general aviation"?

@Harper Not really. I kind of understand it meaning "non commercial" aviation, but beyond that I'm basically clueless

@YAHsaves Had a hunch.  I asked so people could calibrate their answers to your skill level.

Contact a local farmer and land in their field. Common in Europe. High incident rate but meh, you have insurance.

Per AOPA:  WHAT IS GENERAL AVIATION?
THE SIMPLE ANSWER:
General aviation is all civilian flying except scheduled passenger airline service.
AS SIMPLE AS THAT?
Yes. And as complex as that. General aviation
includes flying as diverse as overnight package
delivery and a weekend visit back home; as different
as emergency medical evacuation and inspection
trips to remote construction sites; as complimentary
as aerial application to keep crops healthy and
airborne law enforcement to keep the peace.

To get a better understanding of how GA tends to work, I'd suggest look at the numerous YouTube channels with pilots flying their aircraft.

Entirely for entertainment purposes, I suggest visiting Aviation101 on YouTube, where you can see quite a few interesting things, such as flying a 172 into Chicago O'Hare, or what it takes to fly one from Florida to California. (But remember that YouTube videos are not a substitute for flight training and should not be used as such.)

The first thing you usually do as a pilot is to look at a sectional chart, which shows all the airports and airspace in the area you want to fly (and transit). They look like this:

You can see that the Orlando area offers a number of airports. I would avoid anything with the word "International" or "INTL" in the name. Mostly these airports cater to commercial traffic; GA traffic is allowed but usually requires a lot more work to get you in, especially if you are only VFR (not instrument rated or on an instrument flight plan).
You can see Orlando Apopka (X04) in the upper left corner, but also available are Executive (ORL) just above Orlando International or Kissimmee Gateway (ISM) in the lower center/left. If you want to make sure the airport has fuel, these are denoted by the "ticks" around the airport symbol:

If you want to look at more sectional charts, they are offered for free on sites such as Skyvector which also has flight planning tools.
To answer your other questions:

Which brings me to my question, if the pilot of a small aircraft wants to land in place far yonder what's the best way to plan for this?

Flight planning is part of your initial pilot training. By the time you earn your PPL you will have planned a number of cross-country flights (albeit not that far as Texas->Florida). It starts out by picking an airport and looking up the information in the chart supplement along with one or two alternates. You then call the Fixed Base Operator (FBO) and ask about fuel rates and overnight parking, and then continue on with your flight planning tasks (like checking weather, routing, etc).

Is it common practice to call all the "small guys" in the area first and see if they're willing to work with your flight schedule.

Calling the FBO you intend to visit is advisable, especially if you need to use services like parking or crew cars. This lets them know to expect you and they can tell you what they charge. Some smaller airports won't charge for ramp tie-downs if you buy a certain amount of fuel, etc. Some airports don't have an FBO so they are "self-serve", meaning you pull up to a gas pump just like in your car and fuel yourself.

If they gave you the go-ahead to land and store your aircraft in their facilitates is there any paperwork you should sign to protect your aircraft in the case of theft/vandalism?

Leaving your airplane at the airport isn't like parking it in the parking structure. Airport access is tightly controlled, especially at airports that have FBO's or operating control towers. Some smaller airports don't have that and if you know how to find the codes you can pretty easily get through. Either way though, vandalism/theft is usually a non-issue. The biggest worry you have is weather. If you are really concerned about your aircraft, you can ask the FBO if they have a hangar and if there is space available. Storing your aircraft in the hangar can be very expensive. Typically you just tie down on the ramp and put in some sun-shades.

What if the commercial airport is the only viable "runway" you see close to your target destination? What red tape is involved with landing/storing a small aircraft on commercial landing strips?

I assume you mean a major commercial airport like Orlando International. The only "viable" option to me denotes an emergency, as you should have planned to fly somewhere else and only in an emergency would you want to land at a major commercial airport. If you need to declare an emergency and land, ATC will clear the airspace and make you the only user of that airport. As for storage when you get there, many airports even the size of Orlando International have a GA area where you can tie-down, but getting fuel and even the ramp space will be very expensive.

Say I'm the proud new owner of a Cessna 172.
To celebrate I want to fly my family from Texas to Orland Florida for a weekend visit.

Just FYI, a Cessna 172 is not a "family trip" aircraft. Two adults, one kid, and baggage will pretty much max out the aircraft. You can remove fuel to add more weight, but then you are puddle-jumping.

Local takeoff is easy enough. I live close by, and I know the locals so I can "borrow" a runway.

Unless the airport is marked private (PVT) you are free to use it and don't have to "borrow" anything. Only airports marked as such in the chart supplement will require prior authorization to land there, so the majority of airports are "public use" and you can just jump in your plane and fly there without warning (as long as the weather is above minimums).

You've gave me the answer to questions I didn't even know to ask! It's awesome there is an infrastructure setup for GA aircraft. Looks like I have to study how sectional charts work now.

Don't assume that the OP's family is two adults and a kid - it could be one adult and two kids, one adult and one kid, one regular-sized adult, one very petite adult, and one kid, two very petite adults and one kid, one adult and one dog, two adults and one incorporeal spirit...

To me, it looks like the OP hasn't even begun his flight training yet. @YAHsaves If you've never even looked at a sectional chart, you're a way off thinking about purchasing an aircraft yet...

@Cloud Fully aware of that fact :D I just wanted to get a feel of what private flying is like. Reading the answers though it looks quite fun, kind of makes me want to start some flight training.

@Sean Even if it was just him, spending 7-ish hours in a 172 doing 110kts (estimated time if staying over land, 9X1->X04) is really uncomfortable. It certainly isn't unheard of, but I would never buy a 172 to use it to take family (or long distance personal) trips frequently. A PA-24 or 182 would be a better choice, IMO.

@RonBeyer Sure, but this poses a different question... would you risk your families lives in a PA-XX for the sake of showboating your (very newly acquired) piloting skills? I wouldn't take my dog up in one personally.

@YAHsaves Go to a local gliding club. It's cheaper, more environmentally friendly, more fun and arguably safer. And you can take one passenger up once you get your certificate / sailplane license.

@Cloud I have a complex endorsement and have trained in a PA-24-180, I have no problem with them. The recent wing spar AD is for the PA-28 and PA-32...

"International" doesn't automatically mean "big, busy airport", it just means "airport has customs facilities".  Eckhart International, for example, consists of an 1100-meter grass runway.  It's an "international airport" because the Porthill border crossing is a five-minute walk from the north end of the runway.

@YAHsaves You can contact a local flight club and ask if they offer discovery flights, if you want to get a bit of a feel for what flying a small airplane is like without committing to spending thousands of dollars or more. A discovery flight should set you back on the order of $100-300 and should get you the better part of an hour in the air with an instructor. That instructor can then inform you about what realistic options are available in your particular area.

@Mark My home airport is KGRB "Austin-Straubel International Airport". Of course they aren't all busy or that you want to avoid them. The Orlando area is different though, especially for a "newly minted pilot" and I would avoid them just because you will face higher scrutiny there. I thought it was a little more obvious, but for this post I'm talking specifically about the trip from Texas->Orlando for a new pilot in a new-to-them aircraft.

"Unless the airport is marked private (PVT) you are free to use it and don't have to "borrow" anything." Are military airbases marked PVT?

Generally people don't fly GA aircraft into major international airports. It can be done, but the landing fees tend to be high, fuel is expensive, and they often charge quite a bit for parking. If you are flying to Orlando in a C172 you would likely land at one of the smaller airfields on the perimeter of the city, say X04 Orlando Apopka Airport which appears to be run by the city and has nice cheap fuel. Generally you don't need to call ahead or make any special arrangements unless you need something special done. You just show up, talk to the FBO and they will find you some ramp space to park your plane. Ramp fees widely vary from free, to free if you buy some gas, to a few bucks a day to somewhat egregious at fancy airports.
Landing and parking are controlled by different entities. Clearance to land at a towered field is granted by the tower, at an non-towered field there is no clearance required to land. Once on the ground your ability to park is controlled by the FBO's or airport owner.

That airnav.com website shows you basically everything! I had no idea a database like that existed. I was trying to google "local airports Orlando" but nothing like this came up. Thank you

@YAHsaves Airnav is great. Not just for that information but also for rough flight planning, especially in areas you have no charts for (yet).

skyvector.com is another great site for planning, has VFR charts of the US that you can pan around in; it calculates airport to airport distances with time en route estimates, it can also show suggested routings; it shows TFRs for presidential visits, ballgames, etc. ; it shows area of weather concern. Then aviationweather.gov for seeing radar, satellite, winds, etc., all kinds of aviation related weather info.

Minor nit. There are no "landing fees." There are FBO parking fees, but not landing fees from the airport. You can land and takeoff all day long and never see a bill for that.

@acpilot Not true. There are airports that charge landing fees. As in, if your wheels touch the runway, then you owe money.

Where in the US is that true? Serious question. I have flown to many, many fields of all sizes in all kinds of planes and never once paid a fee to simply use a runway as a part 91 or 135 operator.  Ground services, sure.

Landing fee - Hanscom (BED, near Bedford, MA), charges a Departure fee. MassPort charges the fee, not one of the FBOs.  The bill actually comes from a company in Ohio. $10 for departing (for non-based aircraft I assume).

@acpilot both Philadelphia airports (KPHL and KPNE) have $5 landing fees for GA aircraft. The topic is covered in this question

Huh.  Good to know.

@acpilot Santa Monica (KSMO) charges $5.48 per thousand pounds of your certified max landing weight.

Those people suck.  What is happening at SMO is criminal.

@acpilot, what's happening at SMO is that 18 million people are being served by only 17 airports.  They need to do something to keep demand down to manageable levels.

No....the closure thing.  Not the fees thing, but those are bad too.

@CrossRoads what if you made an emergency landing? Do you have to pay a departure fee to take off again if you didn't intend to land there?

US airports are broadly divided into public and private. Public means anyone can use them, usually because that was a condition of receiving public funds, and private means you need the owner's permission.
Most private airports are either a grass strip on a farm or a neighborhood of hangar homes, so few people other than the owners have a reason to use them anyway. Of course, anyone can use them in an emergency, which trumps all other rules. Hopefully your trip doesn't involve an emergency, so you can ignore those.
The vast majority of planes, however, are at public airports.  Nearly every county in the US has at least one, and most cities have several; they are far more numerous than the small subset (a few hundred) served by airlines that the general public thinks of.
However, the public funding often covers just the runways and taxiways, and the ATC services (if any). At many airports, the parking areas are owned or leased by a Fixed Base Operator (FBO), which may charge parking and handling fees. However, such fees are often waived if you buy fuel or other services from them.
FBOs appreciate you calling ahead, but most customers just show up, as with any other retail business. In most cases, the only paperwork is the bill/receipt.

I like to break it down as commercial airports and general-aviation airports.  The latter doesn't have a TSA presence with the usual luggage scanners, etc., because they don't have any passenger operations other than charters and private flights.
Commercial airports will take GA traffic, but may deter it with high fees if they don't have the space (SFO) or slots (Heathrow).
So you have a lot of airports - certainly the wide majority - that are all-GA all the time.  A lot of airport authorities have them as bookends - like DTW (commercial) and YIP (GA).
Some are both at once. Take OAK, which on paper is a stupendously busy commercial airport, and you'd think "oh noes, they can't take GA traffic!". Actually, all that commercial trade flies from a single runway, 12/30. The GA side is a sprawling operation, with two Learjet runways 10R/28L and 10L/28R, and a Cessna runway (15/33). The 737s don't want those runways because of the 20 minute taxi to the commercial side. And the GA side is spectacularly underused, despite having capacity for SFO-tempo GA flight ops.  (Location notwithstanding, might not be a bad place to hold "Oshkosh", you could even send the DC-3s and An-2‘s over to 12/30 so they don't disrupt the flow.)
This has nothing to do with "international" or not. That has to do with whether Customs & Immigration has established a port of entry there.  Which you must pass through for your first landing in a country.  Near borders it is common to see GA airports that are international.  For instance OAK is international for the commercial and private jet flights to Canada and Central America, not the Cessna crowd.
There are also military airports, which are off-limits unless you are having a problem (see the first few minutes of Strategic Air Command).  In that case, don't be the guy who ran out of gas as flying right over top of Dover AFB.  When Dover controllers heard about that, they said "he...should...have...asked..."


text:
What is this WWI aircraft?
I recently acquired what appears to be an extremely rare photograph. It was purchased at an estate sale auction in Europe. The photo was listed simply as "Flieger in seinem Doppeldecker "Bülow" (aviator in his biplane "Bülow"). No other I.D.

The "Flieger" is recognizable as Ace Leutnant Walter von Bülow, but he seems to be sitting in the rear seat, of a 2-seater biplane. This is evidently a photo from very early in his service (FA22? FA300?), before he joined Jasta 18 where he flew an Albatros D.III. This plane is clearly no Albatros D.III.
Based on the triangular bracing over the fuselage, I suspected this could be some AEG or Rumpler design.  What's leaving me completely confused, is that the wings have a third pair of struts, just visible at the left edge of the photo. Could this be a single-engine two-seater bomber of some type?
The photo doesn't give much to go on, but I know this aircraft must be from early in the war; probably pre-1917.
Can anyone help me identify this plane?

Can you tell us what is written under "Bülow"? or add a close up view? It seems to start with "Deutsche". Also on this page, the service records: Apr 15 to Sep 15: FEA 5 ⌾ Sep 15 to Mar 16: FA 22 ⌾ Mar 16 to Jun 16: FA 300 ⌾ Jul 16 to Dec 16: FA 300 ⌾ Dec 16 to May 17: Jasta 18 ⌾ May 17 to Dec 17: Jasta 36 ⌾ Dec 17 to Jan 18: Jasta 2.

Gypaets answer below appears to be correct: Deutsche Flugzeug Werke Leipzig.  There also appear to be some numbers underneath "Leipzig".  I can make out " 2   5  " then something else - might be letters...

My best guess for the text below BÜLOW is "Deutsche Flugzeug Werke (newline) Leipzig".

Having three pairs of struts on each wing would make it a DFW B.I, C.I or C.II, as later models only had two pairs of them.

The small gap between the wings matches the photo too.
While some prototypes got a machine gun, the standard version of the DFW B.I was unarmed.
According to the book "German Aircraft of the First World War" (Peter Gray & Owen Thetford) the only difference between the C.I and C.II version is the position of the pilot (C.I: pilot in rear seat). Another source mentions the change of the machine gun from Parabellum to a synchronized one. A synchronization gear only makes sense attached to a fixed machine gun below the upper wing.
With a gun over the upper wing and assuming that Bülow is sitting in the pilot's seat, I'd say that the airplane is a DFW C.I.

Deutsche Flugzeug Werke Leipzig appears to be correct. There also appear to be some numbers underneath "Leipzig". I can make out " 2 5 " then something else - might be letters... .  So based on your plane ID, and the service record "mins" reported - which I also believe is correct - this is definitely pre-Jasta 18 service.

I would venture the guess that the numbers are a date: 2.5.15, a manufacturing or commission date, so that would place the photo in Bülow's time in the Feldflieger-Abteilung (FFA) 22 which used early C-I types of different manufacturers. I would rule out an earlier time in the Feldflieger-Ersatz-Abteilung (FEA) 5 which was a training unit and most likely did frown on the personalisation of aircraft and would fly unarmed. After 3 air victories in late 1915 he would have been in a better position to put his name on a fuselage. The FA 300 used Pfalz single-seater monoplanes.

Good Grief. There are no other known photos that clearly show von Bülow in the cockpit of his plane; this photo is from before he became famous; and photos of this type of plane are likewise very rare. I want to sell this photo, but how in the world do I set a price on such a thing?  It's irreplaceable!

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
When do pilots use NOTAMs?
Usually, pilots will check NOTAMs during pre-flight prep. Are there some situations where they use them in a specific flight phase? If yes, in which case would it be useful?
Thank you

NOTAMs are a pre-flight planning aid. You plan around the NOTAMs published prior to takeoff. Depending on the nature of the NOTAMs, every phase of flight could be affected including the decision to fly at all. Plan properly, and you won’t have to use any further NOTAMs. In-flight planning will be done utilizing information gathered from the AFD, ATIS,  ATC and FSS. A single pilot inflight would lack the time to keep up with new NOTAMs without help. It has only been relatively recent that in flight NOTAMs were possible for your General Aviation pilot other than the aforementioned radio sources.

NOTAMs are a planning aid. Before flight you look at the NOTAMs that are applicable to your route, including diversion airfields, and extrapolate the information you need. A NOTAM may make you change your route, or take a note to use a different frequency or procedure. You may make a notation on a map, for example, or a hand-written note on your pad, presuming you use one.
Once flying it's unlikely you'd refer to NOTAM text, they are terse and can be cryptic, and often require plotting on a map. You may bring a printout of frequency changes I suppose, but that would be the extent of it. Some navigation systems can use NOTAM data to enrich a moving map, which is handy as a visual reference.

Use or check? NOTAMs can give pilots of a wide range of information, so in terms of use each NOTAM is different. For example, they might tell the pilot that a frequency has changed - so that's something they may need to integrate into their flight at the relevant point.
Or, the classic, is that there are standing NOTAMs in the UK that overflying Ukraine and Syria aren't recommended. Not something most pilots need to worry about.
There is no expectation to check NOTAMs after departure, however.


text:
Are the firewall and forward pressure bulkhead different components?
Suppose in a single engine aircraft, where the engine is located near the nose of the aircraft. If the cabin is pressurized, I know there will be a requirement of pressure bulkheads, both in the rear and the front to prevent the excess pressure from leaking out (and bearing the pressurization stresses). Now my question is that is the firewall, which is used to keep the heat of the engine (and flames if the engine ignites) away from other components of the aircraft, same as the forward pressure bulkhead i.e. does the firewall in this case have 2 roles: being heat resistant and at the same time bearing the pressurization stresses due to excess pressure inside the cabin.


text:
How much is alpha induced angle?

I know that alpha induced rise with increasing AoA but how much is alpha induced in reality ,are we talking about 1-2 degrees or more?

From https://aviation.stackexchange.com/a/75333/41375, at lift coefficient of 0.4, it's about 0.9deg for an elliptical planform.

The induced angle primarily depends upon the following:

Coefficient of lift
Aspect Ratio (AR)
The correction factor $\tau$ (needs to be accounted for if the wing platform is not an ellipse. If the wing platform is an ellipse, then $\tau=0$)

All three are related the with the following equation:
$$\alpha_i[\text{rad}]=\frac{C_z}{\pi AR}(1+\tau)$$
The table below provides the values of $\tau$ for a rectangular wing.

You can use these values and NACA Report 824 to calculate the actual induced angle of attack for a rectangular wing for any possible airfoil.
For instance, using $\text{NACA} ~65_1-412$ airfoil at $\alpha_{\text{geometric}}=8^{\circ}$ and $AR=9$ it follows that $\alpha_i=0.05~\text{rad}\approx 2.86^{\circ}$.
It varies greatly in relation to the angle of attack, as low as $1^{\circ}$ in high-speed flight with low angle of attack and as high as $3^{\circ}-4^{\circ}$ at low-speed flight for a rectangular wing aircraft.


text:
How does a UFO fly so fast?
Now, we have seen the UFOs by US Navy's onboard cameras, they are so fast and they do change their directions very quickly. How do they do so almost breaking the laws of physics?

Since the object is, by definition, "Unidentified", it's going to be difficult to detail how and why it is able to fly quickly and have such sudden direction changes. At best, this question will garner purely speculative answers (unless a member of the US Navy with intimate knowledge of the particular incident happens to stop by and be willing to share what has probably been deemed Classified or Secret information), and this particular slice of the web doesn't deal well with speculative answers. Please take the [tour] and read the [help] to see if you can bring your question in line...

...with expected community standards. Additionally, it would be most helpful if you would [edit] your post to at least include a link to the video in question, as not all of "we" have seen said footage.

Since this forum is for fact based questions and answers about known and identifiable aviation subjects, it does not lend itself to conjectures or opinion based discussions. You might try the Sciencefictionstackexchange or the Physicsstackexchange for your answer.

If you want a real answer to your query, you might change it to read something like, “What design considerations would have to be taken into account to make an aircraft accelerate, decelerate, and/or change directions so quickly? And, how do we make such velocity changes survivable by pilots?”

An answer not based on opinion is possible, no need to close this.

I don't think speculation is on topic here and I fail to see how this question can be answered without speculating.

@Hobbes This is a fact-based site. UFO questions will be on topic when they are at least identified, and thus no longer can be called "unidentified flying objects".

@ZOMVID-20  have you read the link in my answer? The objects have been identified.

This is about 3 videos released by the Pentagon. The vehicles in those videos don't fly extraordinarily fast. The 3 videos in question show normal aircraft and a balloon. The reported speeds are incorrect due to imperfections in the equipment used and optical illusions.


text:
How to find the plane a FDR came from?
I'm trying to find out which plane a Sundstrand UFDR came from and have narrowed it down to 5 possible planes.   How can I confirm which of the 5 planes the FDR recorder came from?
I did a lot of research and found out that Boeing had a contract to install Sundstrand UFDRs into their 767 and 757 planes.
The Sundstrand UFDR in question has one of the tags stating "BOEING PART NUMBER" instead of "CUSTOMER PART NUMBER" and a date code of 8822, made the 22nd week of 1988.  It also has two SAS identification tags on it, from SAS airline.
From SAS annual reports archived on their website, they stated they had ordered five 767s, and indeed five 767-383ERs were delivered to SAS from Boeing in 1989.
SAS no longer owns any of these 767s, 2 are listed as still active, one as stored and 2 are listed as having been scrapped, one scrapped in 2010, and the other in 2017.
My research also shows that this particular model UFDR, would have had to be removed from all planes it was in, by Jan 1st, 2016, as all such magnetic tape FDRs had to be replaced with digital chip technology.
Now the ONE 767 in this group was scrapped, while a UFDR would have still been allowed.   The other plane was scrapped after it would already have had the newer digital chip storage FDR in it.
What typically happened to these Sundstrand UFDRs in 2016 when they were removed from planes and replaced with the newer ones?
Where and how does one go about finding records on which serial number FDR was on a particular serial number Boeing plane?
Being I have narrowed it down to 5 planes, how do I now confirm which of the 5 planes it came from?

You would need the maintenance records of each of those aircraft to determine this.  Good luck!

Equipment like that isn't necessarily on a single aircraft, only.  The airline would probably have a small stock of FDR's, and if one malfunctions or otherwise needs to be swapped out, one from stock would replace the one from the aircraft.  And when that one is repaired, checked & good to go, it returns to stock, waiting to be similarly installed. So the box you have may well have been in more than 1 of the 5 jets at some point. And without the records tracking removals & installations by serial #, there's probably no way to know which one(s).

I figured it could have been moved at some point, especially once after the planes were in possession of other airlines, (which brings up the question, would they leave the SAS control number tag on it, or remove that and put their own airline tag on it) but as Boeing put these on the 767s when building them, at least it would be nice to know which plane it started on.
Then if I find a photo of its first flight, I know it was on that plane.    Hard to say if it stayed on that plane, unless I can find an accident report from an airline that had it after SAS, with the serial number on it.

Would maintenance records still exist from 1989 - 2016?  And do they follow the plane to subsequent airlines, or stay with the airlines, and new records kept with a new airline from the point they get the plane?
I also wonder if Boeing still has records from planes they put together around 1988-1989.

Such records certainly could exist, but they are definitely not in the "public domain."  It's possible the right person the the maintenance department at SAS or Boeing could find this out, but it could be quite the project to find & persuade that person to spend the necessary time and effort. If it'd be allowed at all.

Boeing will have records dating from the earliest 767, and maintenance records will also exist. They'll be needed for accident investigation, if nothing else. And given @RalphJ 's comment above, it's quite possible that your FDR was always a spares-stock item, and wasn't installed on any aircraft at delivery.

When it was removed from the original plane, I don't know, but it was indeed the original UFDR put on a new 767-383ER when Boeing delivered it to SAS.
This one has the unique luck of the link between Boeing, the model UFDR, and the contract between those two companies and all 767s, the SAS tags on it, and the year date code matching when SAS got five new 767s from Boeing.
If not for the link of all of those things matching perfectly, I would not have been able to determine it was an original from 1 of 5 planes.
Now for some luck to narrow it down to 1.

I'm still also trying to find out how these used flight data recorders come into the public market.   From scrapped planes?  Or are they kept by the airline before being left at the boneyards?   When they become obsolete technology and required to be replaced, (like this model was by 2016) do the airlines sell them to used aircraft part dealers?  The Underwater Locator Beacon was removed.  Perhaps because it was still good and just put on the new FDR that replaced it?   Not sure if this is a helpful clue or not, being sometimes you find them still with the flight recorders.

Another interesting clue from Lauda Air, who ordered a Boeing 767-3Z9ER that was delivered on 16 Oct 1989, and crashed 26 May 1991, in the crash report lists the Sundstrand UFDR (BXUS) serial number as 5632, close enough to the SAS one.
So this plane had the same flight recorder in it almost 2 years later, that came with the plane from Boeing.
One of the five 767 planes SAS originally had, had an accident after another airline owned it, but there is no mention of the serial number in the report.   This could have verified or eliminated that plane from my search.
Still searching.


text:
Why aren't variable swept wings being used in newer military aircraft?
After finding out how well the variable swept wing design served the F-14, why hasn't it been used more often (outside of a select few)? Almost all of the fighters after the cold-war era haven't used variable swept wings.
Bonus question: is there any significance to the way the F22/F35 wings are shaped almost like triangles?

(source: foxnews.com)

For your bonus, see this question.

Your two questions, while both related to wings, are really not well related to each other and would do better in the SE environment as separate questions.

The main advantage of variable sweep wings is that they reduce drag over a wide range of Mach numbers.
However, the variable sweep wings are not being used in present day aircraft for a variety of reasons.

The variable sweep wings are heavy and mechanically complex, affecting performance and maintenance.
The swing mechanism takes up too much space inside the wing that could be used for fuel.
It is difficult to position hard-points in the swinging part of the wing, affecting payload.
Advances in aerodynamics and better engines mean that the drag reduction using varying the wing sweep is not so critical anymore.
Also, the newer combat aircraft are not trying to outdo each other in speed, trying to gain the edge using better situational awareness, stealth etc.

However, the most important reason for variable sweep wings falling out of favor is that they are nearly impossible to be made stealthy. One way to make the aircraft stealthy is to reflect the Radar energy away from the source. In order to achieve this, the wings of stealth aircraft are designed in a specific way.
However, if the aircraft have a variable sweep wing, this condition is all but impossible to achieve. If stealth is still required, it has to be through more Radar absorbent materials, which further increases weight and maintenance requirements. The last variable sweep aircraft, B-1B, for example is designed to be a low level penetrator, unlike B2.
Because of these reasons, the variable sweep wings have fallen out of favor.
As for the second question, the wings of F22/F35 has basically a trapezoidal wing configuration, which gives a high performance at high speeds.
However, the main reason for using this type of wings is the excellent stealth characteristics they provide compared with other type of wings. One disadvantage of this type of wings is that their low speed performance is not up to the mark, but this has mostly been overcome by the use of improved control surfaces (like flaps, slats etc).
Interestingly, USN considered a variable sweep F22 for carrier operations, but the project was ultimately dropped.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
How do pilots travel from remote private airports after landing?
What if you fly your own personal plane to a small private airport in the countryside that has no public transportation? I imagine that most pilots don't have a car parked at each private airport they intend on flying to. That is, of course, unless your car is small enough to fit inside your plane. If you want to go somewhere twenty miles from the airport, for example, do you just call a taxi or ask a friend in that town to pick you up in their car?

If you want to go twenty miles from the airport in the US, you probably can fly into a closer airport.

@MichaelHampton In that case, let's make it a short enough distance that there won't be any other airports, but long enough that you can't walk. 5 miles, for example?

@K Man: Don't know about everyone, but I'm perfectly capable of walking 5 miles, or 20 FTM :-)

i've watched enough TV shows and movies that... i feel like they always gloss over this part.

@MichaelHampton New England isn't the US.

@chrylis-onstrike- Did you have some reason for posting this? It doesn't make much sense without context.

@MichaelHampton In Texas, much less farther west, many places are more than 20 miles away from an airport.

@jamesqf How about a five-mile walk through the desert in the middle of a heat wave, across the plains with a windchill of below 0 or along a somewhat busy road with lots of twists and turns and a narrow breakdown lane for pedestrians?

@KMan - Texas has tons of airports. In some areas it seems like Texas has an airport every 10 or so miles radius of each other. But, there is still more open land than airports, especially West Texas. The FBO courtesy car or Über are still your best options. Especially in towns where a taxi or public transportation will be rare. I can run a marathon, walk even farther, or cycle 100 miles through 110° Texas heat. But, I would not be able to fly an airplane immediately afterwards.

Walking is more of a mental barrier than anything else. Our ancestors did a lot of walking every day.

@K Man: Sure, no real problem.  Though when I hike in the desert, I avoid the heat of the day and do the hiking mornings & evenings, or even into the night.  For the plains, I'd prefer cross-country skis - and I really like the few days it gets around zero hereabouts.  Busy road?  Hey, my thumb still works :-)  (But just as a general rule, I'd avoid flying to such places if I wasn't comfortable with whatever means of transport was available at the destination - and my few bad experiences involve commercial flights to major cities.)

A pilot I know used to own a folding motorcycle for such purposes; when stowed it was about the size/weight of a large suitcase and I'm fairly sure (this was 30 years ago) it would fit through the luggage hatch of his Cessna 172. It could carry two people but at 49cc, and a two stroke engine at that, it was certainly a leisurely and perhaps fragrant way to travel. Being classed as a small motorcycle/moped there were a different set of licensing rules applicable that meant one didn't have to have the class of driving license as would be required for a larger engine
On occasions where there was a need to transport more people they were usually going to a place where one person could use it to retrieve a larger vehicle from somewhere at the destination, though a couple of times there was a bit of shuttling to do, one pillion passenger at a time
It seems they're still around and look to have modern, luxury facilities, such as lights and mud flaps, compared to the one I remember:

A bicycle, motorized or otherwise, might be a better fit for smaller planes.  Possibly multiple bikes if you plan to bring passengers.  Much less weight to carry, and can probably be folded up even smaller.

You do whatever you can.
Sometimes you call a taxi/Uber, sometimes you walk, sometimes you pack a small folding bicycle into your plane, and sometimes you borrow the airport car.
Many small airports in the US have a car (often a retired police car) available for itinerant pilots to borrow.  It's usually a scary rusted out pile of junk, but it works.  If you borrow it you're expected to return it promptly & with a full tank of gas.
It's wise to make arrangements for ground transportation before you arrive - there's no guarantee that any particular option (except walking) is going to be convenient and available.

Not even a folding bicycle: I frequently carried a mountain bike in my Cherokee, and sometimes a road bike.  (Easier if you take the back seat out.)  I'd often fly places just to go biking there.  Note that there's a wide range in "small private airports", from ones that see a lot of traffic and may have a loaner car or two, to backcountry strips that might see one or two planes a week, to handy bits of dry lake & such.

I've seen "shared" bikes around a nearby airport, but suspect they were more for employees to use.

There is no guarantee that walking will be convenient either, just available :-)

In my experience, in the United States, most General Aviation airports, GA sections of the airport, and Fixed Based Operators have one to a fleet of courtesy crew cars. If you are a pilot being serviced by that particular facility, you are given access to a crew car. The length of time you can use the car can be anywhere from one to four hours, depending on the facility. The type of car can greatly vary as well. I have borrowed cars as nice as brand new Infiniti sedans, Chevy Suburbans, Tahoes, Toyota Camrys and Corollas to as crappy as the POS pictured below. Even at unattended airfields, there may be a car pilots can access through the local police department.
Check out the following...
CODE OF THE COURTESY CAR
COURTESY CAR FINDER
FBO COURTESY CARS
The best GA FBOs have even greater facilities than just a car. Many have crew-rest rooms, small theaters, meeting/briefing rooms, full crew kitchens, airport golf carts, and shower facilities. Some even have arraignments with local restaurants for them to provide transportation to and from the restaurant in nicer cars. Same with local hotels. The Class Bravo, Charlie and busier Class Delta Airports will have rental car agencies located in the FBO for overnight rentals. There are many apps and websites that give details of the amenities available at each participating FBO. ForeFlight is one of them that does an exceptional job.
The original poster is assuming that the majority of general aviation airports are accessed by public transportation. In the United States, there are even major Class Bravo airports without a substantial public transportation system. And, the systems that are there are predominantly not used as opposed to shuttles, taxis, and rideshare services. Unfortunately, the GA portions of the airports are located away from the commercial terminals. Therefore, there is not usually access to public transportation except for prearranged shuttles, taxis, and rideshare services.

No A/C and windows that were off their manual (not power) tracks...in Texas...in August.
But, we were thankful to have it so that we could run into town to get a bite to eat.

I amazed that a system like this still exists. It's quite heartwarming.

That's a mighty fine looking Buick.

@Z4-tier - I want to say that it was a Chevy Celebrity. My 35 year old co-pilot had trouble figuring out why it had a square key and a round key but no buttons on either key. He was really floored by the hand crank for the manual roll-down windows instead of buttons. Then, I had to show him the old school way of getting the windows up and down when their tracks (regulators) were broken.

@DeanF. sigh... kids these days...

@FreeMan: IDK, since I'd probably have similar problems trying to figure out how to use those "keys" with buttons.

Why does it have a square key and a round key? The old cars I know have a single key and a set of matching keyholes on both doors, the trunk and the ignition.

@Alexander - It depends on the year, make and model. Ford products switched to a single key earlier than General Motors products. Before that, Receiving two sets of two keys with every car was common. This year Chevy had a round key for the doors and trunk. It had a square key for its ignition. Now, physical keys are integrated into the key fob. Some keys are meant to never make physical contact with the car. I watched an older lady try to start her husband’s Porsche for over 15 minutes before I pointed out she had to place the key fob into a receptacle &press the start button.

@Alexander - My family owned only American cars from The Big Three my entire life until my last year of high school. All were two key cars until maybe my sisters Volkswagen or my Mazda. After that, my parents newer model Cadillacs had two keys with the ignition key having a security microchip embedded in it. Although our Fords had one key after college, our Pontiacs had two keys and a key fob remote even after I got married. I don’t remember having any car after 2000 with two keys.

@Alexander my first car was a 1989 Buick Century. I liked the two-key system (door and ignition) because both keys could be copied at a hardware store just like a door key. Everyone in my family had a set of keys and I had several for when my high school self misplaced one around the house.

Typically the FBO's courtesy car is used, but I've flown into a lot of airports that either do not have an FBO (or the FBO does not have a courtesy car), or it was after hours and no one was around.  Sometimes you might not even have cellular service in the remote airports and they won't have a landline phone in a public area.  That's when you either start hiking or you are glad you brought a bike along with you.  At my age, I'm not going to be doing much hiking... Even walking from one end of the runway to the other is going to kill my old knees.  I can still ride a bike though and it will fit in the back of my plane.  I fly a 4-seater, but no one ever occupies the other 3 seats, so I have room to put a bike.  I have put 2 full size bikes in there once when my wife flew with me.  I think I had to remove the front wheels though.  These days though, with the electric scooters and such, that might be an option for some people.
Back before Hurricane Katrina, I was over at Lakefront airport in New Orleans and the FBO courtesy cars that they had at the FBO which had the military fueling contract were late model Jaguars.  Sure, they were the 6-cylinder engines and this was when Ford owned Jag, so really they were just an overpriced Ford with a Jag nameplate, but that's still a lot more than you saw at other FBOs.

Welcome to Av.SE!


text:
What is this long Bar/Rod on the Boeing MH-47G?
This MH-47G has a thick, long rod at the bottom left front. What's the purpose of this thing?

This is the In flight refueling probe, which can be used for refueling while the helicopter is airborne:

(image source: pinterest.com)
It is almost 9 meters long to make sure the rotors do not hit the refueling drogue. You can see it in action in the following picture:

(image source: chinook-helicopter.com)


text:
How does changes in Power vary the aerodynamic forces on an aircraft?

When we make changes to the Thrust by adding or removing power. In what way does it affect the other forces? As Power controls Rate of Climb or Descent of an aircraft, How is it acting on the other aerodynamic forces to make changes to the Rate of Climb and Rate of Descent?

You need to be careful to say what variables are constrained and what aren't. For example, are you holding the elevator in a completely fixed position as you add power?  (Or leaving the elevator trim in the same position, and refraining from exerting any pitchwise pressure on the stick or yoke.) If not, then what are you doing with the elevator? Manipulating the elevator as needed to hold constant airspeed? Constant angle-of-attack (which is almost but not quite the same as constant airspeed)? Constant pitch attitude? Etc. Without specifying that, the question is really extremely broad.

Re "How is it acting on the other aerodynamic forces to make changes to the Rate of Climb and Rate of Descent?" - related - https://aviation.stackexchange.com/a/56476/34686 -- see especially the two paragraphs under the diagram that shows three vector triangles side-by-side.  Note the suggestion that if L/D ratio is held constant (which implies AoA is held constant), more Thrust actually equates to less airspeed - but we have to make quite a large thrust increase to actually see this in practice.  But maybe you are asking more about how changing Thrust tends to change the trim AoA etc?

Along the same lines, are you asking for an in-the-weeds blow-by-blow description of the pitch "phugoid" that eventually leads to a stabilized climb, or just a comparison of the final steady-states "before" and "after" adding thrust or power?  Your question is more complex than you may realize, and any changes that might narrow it down would help.

Besides the changes in the thrust force and its follow on effects on lift etc., there are trim changes with power. The changes depend mainly on the location of the thrust line relative to the vertical C of G, and in single engine propeller driven airplanes, the effects of propeller wash on tail surfaces where the surfaces are immersed in the prop stream. To eliminate trim changes with power, the engine(s) have to be mounted so their thrust line passes through the vertical C of G, and have no influence on flying surfaces.
So, engines mounted low, adding power reduces trim speed, and vice versa for engines mounted above the C of G. In jets, this generally this means wing mounted engines pitch up with power, and tail mounted engines pitch down with power.
In a propeller single, the thrust line is usually very close to the vertical C of G, but adding power reduces trim speed by increasing whatever trimming load is being applied to the tail (usually down relative to the wing) via stronger airflow. If you go from cruise to climb power in a Cessna 172 while trimmed at 80 kt, when the plane settles down in the climb you will notice the trim speed as dropped a few knots, and that's almost all from the higher energy propeller wash.

The rate of climb is:
$R/C=\frac{\left(T-D\right)V}{W}$
So, increasing thrust (while leaving angle of attack constant) will leave lift coefficient constant, drag constant, airspeed constant, etc.  But it will increase the rate of climb.
If the aircraft has the engines mounted with the thrust line substantially above or below the center of gravity, the aircraft may experience a pitch up or pitch down moment with a throttle change.  However, this pitching moment is not a primary control mechanism and is not relied on to cause the aircraft to climb or descend.
In general, it is preferred to minimize this kind of effect during the design of the aircraft.

Your figure tell you the story:
If you add trust, the THRUST arrow will elongate, so you have an acceleration, but it is not applied to the center of mass, so you will have some leverage effect (pitch you upward). You will accelerate until the drag will increase (drag increases with speed).
But if you got faster, you get more lift, so you will go up, and also because the center of mass is not at the same axis as the wings, you get also a pitch downward. Weight will not change, so you get such configuration "for ever" (until you trim).
Note: what I wrote is based on your figure. If you have engines on tail (as many executive planes), you get different leverage (note: also the position, they may be installed higher then drag vector). The same about the position of the center of mass.

But when we Add Power the Nose tends to pitch up right>

@Nish Right. I inverted the pitches. -- corrected


text:
What is meant by a Gimbal Lock and what are the limits of a Heading Indicator and Attitude Indicator?
When we perform a spin in a Cessna 172, I have seen that the Attitude Indicator gets messed up and locks itself into a disoriented reading for sometime. I have read that this usually happens when  when the Pitch limit of around 85deg is reached and the gyro topples.
And as for the Heading Indicator, after the spin it constantly keeps spinning? Is this also because of the gyro toppling and if so what are the limits for the Heading Indicator?

Gyroscopes are attached to gimbals. Usually we need a 3 axis gimbals because we travel in 3 axis.
The illustration on Wikipedia (which I have trouble to insert here) helps understanding how it works: the gimbals is attached to the vehicle frame by the pins. The gyroscope will keep orientation, so the gimbals rings must freely move. So we have the basic of (mechanical) gyroscopes.
The problem is that with some huge movements, 2 rings may align, so you may lose an axis of movement of the gyroscope, so you force the gyroscope to move with your frame, and so you have incorrect attitude. We call it gimbals lock: the when 2 rings align, you lose one freedom of movement (one axis).
Note: also huge accelerations may cause problem on gyroscope (or not calibrating it regularly: the more you travel, the more you accumulate errors). But gimbals locks is particularly problematic: the data is completely wrong.
It was mostly a problem with spacecrafts or acrobatics where you may travel on all directions. As you can see from the Wikipedia figure, how do you place the rings may affect the problematic directions, so we can set the apertures to the less common attitude, but please note that Earth rotate, so at least one ring will do a complete rotation once a day.
Now we have also other types of gyroscopes (accelerometers, one per axis), so without need of a gimbals, and GPS may provide data to reset gyroscopes, as backup or cross-check.

While GPS data can remove position errors from an INS system (which uses gyros internally), since it doesn't provide attitude information, it isn't clear how the "GPS may provide..." phrase of your last sentence is correct. Please clarify. Thanks!

"Now we have also other types of gyroscopes (accelerometers, one per axis), so without need of a gimbals", accelerometers measure accelerations, gyroscopes measure rotations, they are not interchangeable. An INS is built from 3 gyros and 3 accelerometers. However mechanical gyros (gimbal platform) are a thing of the past, new gyros are static and optical (Sagnac effect).


text:
If the RPM of the Gyro is increased due to high Vacuum Pressure. Will it increase rigidity and resist precession?
If the RPM of the GYRO of the Attitude Indicator or Heading Indicator is increased due to high vacuum pressure. Will it increase rigidity in space and resist any force applied and it will not precess? or will the precession be more exaggerate the reading?

it will hold position more tenaciously with a faster-spinning rotor in it. But it will also wear out its bearings faster, and thereby fail sooner, that a slower-turning rotor. Gyro instrument performance is a compromise between locking on and holding a certain attitude or gimbal position, and bearing longevity.

Basic physics will help in understanding (From my ATPL book)
When the rotor is made to spin, the device becomes a gyroscope possessing two properties :

Rigidity (or gyroscopic inertia); and
Precession.

Rigidity
Rigidity is the property of a gyroscope which resists any force tending to change the plane of rotation of its rotor.  As a result of rigidity, the spin axis tends to maintain a fixed direction in space.  Rigidity is dependent on three factors :
(a) the mass of the rotor;
(b) the speed of the rotation (RPM); and
(c) the distance of the mass from the centre of the rotor (radius).
The mass and radius of the rotor determine its moment of inertia.  Rigidity is proportional to the rotor's moment of inertia (I) and its angular velocity (represented by the letter omega)

Rigidity is the property of the gyro which allows the gyro to be used as an independent stable reference.
Precession
Precession is the change of direction (angular change) of the plane of rotation of the rotor caused by an applied force.  The amount and rate of precession is dependent on three factors :-
(a) the magnitude and direction of the applied force;
(b) the moment of inertia of the rotor and
(c) the angular velocity of the rotor (RPM).

Rate of precession is directly proportional to the applied torque(T).
Rate of precession is indirectly proportional to rigidity.

From the text above it is quite clear that if the RPM of any mechanical GYRO is increased due to whatever reason, it will increase rigidity in space and resist any force applied and it will precess mechanically less (aparent wander or precession due to rotation of the earth or travelling still present).


text:
What would be the likely indication on the VOR for the below question?
The answer given on the textbook is figure 2. But How can the Needle be centered if the aircraft is not on the radial?

Perhaps a graphic can help you. See the picure.
The ac is flying with TO indication (radial 120 selected) in a FROM area. This shows that number 2 is the correct answer.

The aircraft is on a radial. Just not the one marked on the diagram.
Notice that figures 1, 3, and 4 all have heading 210° dialed at the top of the instrument. However, figure 2 has heading 120° selected. Since the needle is centered with a "TO" indication, this indicates that the plane is on the 300° radial (the reciprocal of 120°). In other words, the plane is northwest of the VOR, which matches with the diagram.

You can rule out 4 straight away - it is flagged as Off.
It is worth noting that the horizontal marker blips on a CDI represent 2 degrees when tracking a VOR (the first 2 degrees being the edge of the central circle).
So with that in mind number 1 indicates something like 5 degrees right of track, which would put you on the 215 radial from the VOR. The image clearly does not show an aircraft on the 215 radial.
A similar picture for 3 showing 8 degrees right of 215 radial to the VOR which would make the aircraft on about the 022 radial - again clearly not the case.
So that just leaves 2 which as the other answer correcty says matches the picture.


text:
What is the AMIS?
What is the Aircraft Maintenance Information System (AMIS)?
Online I found only a little information, in particular here:

The Aviation Management Information System (AMIS) is used to collect,
  store and analyze information about the usage of aircraft within
  Forest Service controls.

It is not clear if it is an embedded system, a general database, if it is still in use and where.
To be clear: I DO NOT want information regarding the AIMS (which is the brain of the IMA in the B777). I am looking for a different system called AMIS.

The first line of your question says "Aircraft Maintenance", but the link you posted calls it "Aviation Management". Which is it? My interpretation of the page you linked to is that it's a proprietary tool used in firefighting; see here. Or did you find some information that suggests it's something different?

AMIS (Aircraft Maintenance Information System) is a ground commercial application based on Oracle SGDB. AMIS company in the Netherlands was created after the success of AMIS application, by their programmers. Don't mix with AMIS (Aviation Management Information System) a generic wording for tools onboard aircraft or on the ground.


text:
Which are the requirements for the water supply on board?
Which are the requirements for the water supply on board of a commercial airplane? I know that there are minumum mandatory requirements, but I don't know where to find them and how they can change with the category of the aircraft. Surely there are different requirements from a small turboprop without a toilet to a A320.

On board what? A private helicopter? A small prop plane? A huge passenger jet? A short domestic flight? A long intercontinental flight? A military fighter over enemy territory?

It looks like it's complicated, at least in the US: three different agencies are involved, and only one of them is aviation-related.

The IATA standards as per the IATA Drinking Water Quality Pool are based on

ISO 17775, WHO requirements or EU/98/83/EC or those set by the civil aviation authorities of the participating airlines

Source
Airlines and operators will periodically test their water in aircraft, ground service vehicles, and filling stations for bacteria contamination (E-coli, coliform, etc).
Some aircraft may not actually have potable water tanks or may have removed them. Horizon Air operates their Q400 Dash 8 aircraft without potable water.


text:
What does TRMSN mean in takeoff obstacle notes?
In the takeoff obstacle notes for KMDT Rwy 31, it lists a Trmsn tower. What does Trmsn mean?

Are you referring to this?

Link
I think that is pretty clearly a "Transmission Tower", like a radio-antenna obstacle to be avoided.

So, "transmission tower" is too long and gets abbreviated, but "power transmission line" is spelled out?

The transmission tower is specified as 1.5NM away, but the Power line is 1194 feet away.
Mixing and converting non-associated units!  I have no idea what the conversion factor between feet and nautical miles is!

I'm sure this is right too, but a source of abbreviations is usually available in aviation to be definitive.

@abelenky: 1 NM is 6076.12 feet.


text:
Difference between accuracy, integrity, availability, continuity, and functionality
My understanding is that accuracy is how close my estimated position is to my actual position at a certain point in time.
I don't really understand how integrity is different from accuracy. Continuity also seems to be just a synonym for Availability. This sentence confuses me: "PBM can be defined in terms of accuracy, integrity, availability, continuity, and functionality required ..."
When you use five terms to describe a thing, each term should be able to be defined in a way that makes it obviously different from the other terms. Can anyone help me?

Try this for size:

Accuracy = Precision in locating your position with minimal error.
Integrity = Position signals with the required precision can be relied upon to be valid when being received.
Availability = Integrity of position signals can be counted on all the time. No or minimal outages.
Continuity = Signal integrity is consistent across time and space while switching between signal sources.
Functionality = Ability to use the position signals to generate practical and useful results in different ways.

Expanding: if you have good accuracy, you do not need integrity, but how do you know you have accuracy? GPS may gives you some accuracy, by design, but you cannot know if the antenna broke or if the chip is misbehaving or some interference. So you need integrity (either redundancy possibly with different methods, or regular automatic functional checks on different components). -- it is much about being in real world, not an ideal world. Unexpected conditions and hardware failure are real things.

You can also have false accuracy (spoofing).


text:
What is MILAIP referenced in International Notams?
When looking at notams on the DAIP. There is a line referencing a publication or website I cannot find.
ATS COMMUNICATION FACILITIES.
TWR SERVICE LIMITED DUE TO 'SIGONELLA GROUND' NOT PROVIDED.
REF MILAIP AD 2 LICZ 1-11. 1700-0700, 01 MAR 17:00 2024 UNTIL 29 MAR 07:00
2024. CREATED: 01 MAR 14:57 2024
What is MILAIP AD 2 LICZ 1-11 and where can I find it?

AFOD MIL AIP links

MILAIP = Military Aeronautical Information Publication.
You wouldn't normally have access to these unless you are active duty.  If you have a need to fly into Sigonella you should call and get a copy.

Some MIL AIP's are publically available. For example Netherlands: https://english.defensie.nl/topics/milaip-military-aeronautical-information-publication and Denmark: http://www.flv.dk/milaim/milaip_online.html


text:
Is 200FPNM required up to the MSA or to the MOCA in the PLMTO3 SID
On the PLMTO3 SID out of KCHS, Rwy 15 has standard takeoff mins.
From the AIM 5-2-9.e.1.

Unless specified otherwise, required obstacle clearance for all departures, including diverse, is based on the pilot crossing the departure end of the runway at least 35 feet above the departure end of runway elevation, climbing to 400 feet above the departure end of runway elevation before making the initial turn, and maintaining a minimum climb gradient of 200 feet per nautical mile (FPNM), unless required to level off by a crossing restriction, until the minimum IFR altitude.

My question is, do I need to ensure my aircraft can maintain 200FPNM up to the MSA, which would be 3100MSL, or just to the MOCA from PLMTO to Grand Stand VORTAC.
My thought would be that I have to ensure that the aircraft can make 200FPNM to the MSA since there are no MOCAs or MEAs published from JAYLN to PLMTO. But If that is the case then why do they even bother publishing a MOCA from PLMTO to CRE. There would be no point to climb 200FPNM to the MSA and then descend after crossing PLMTO.!]2

The Pilot/Controller Glossary defines:

MINIMUM IFR ALTITUDES (MIA)- Minimum altitudes for IFR operations as prescribed in 14 CFR Part 91. These altitudes are published on aeronautical charts and prescribed in 14 CFR Part 95 for airways and routes, and in 14 CFR Part 97 for standard instrument approach procedures. If no applicable minimum altitude is prescribed in 14 CFR Part 95 or 14 CFR Part 97, the following minimum IFR altitude applies:

a. In designated mountainous areas, 2,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown; or
b. Other than mountainous areas, 1,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown; or
c. As otherwise authorized by the Administrator or assigned by ATC.

The only part of the route which has an altitude "published on aeronautical charts" for the "airway and route" of the PLMTO3 departure is the segment from PLMTO to CRE (which technically isn't even part of the overall SID, it's a transition route). That means for the rest of the SID up until PLMTO the MIA is going to be either bullet point b or c from the definition, which in either case is going to end up being 3000' MSL as you pass northwest of a pair of antennas in the vicinity of LOIRN. (If not for those antennas the MVA would be down at 1600'.)
Note that you have a good 12 or so track miles to climb from CHS, at essentially sea level, to a point midway between JAYLN and LOIRN, at 3000'. Depending on how long you wait to start the lefthand turn once you depart Runway 15, that's 250 FPNM or even less. You can do some more precise plotting using the VFR sectional and Skyvector if you really need to, or you can just plan for 250 FPNM and call it a day.

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In all cases continued obstacle clearance is based on having climbed a minimum of 200 feet per nautical mile to the specified point and then continuing to climb at least 200 foot per nautical mile during the departure until reaching the minimum en route altitude unless specified otherwise.

The departure route has all aircraft climb to and maintain 4000. So you need to keep up the gradient until reaching 4000. The MSA does not appear anywhere on this departure and it's not a great idea to start looking at approach charts and trying to extrapolate from them to cheat on your minimum climb gradient.
MOCA's aren't left off of charts just because they might not be useful in some specific situation. If you start picking up icing right after PLMTO knowing the MOCA would be very useful indeed!
If you're part 91 and not assigned a SID, you legally don't need to respect takeoff minimums and can DIY your own approach (let's not discuss the wisdom of this for now). This may well involve looking at approach charts or VFR charts to figure out the minimum safe altitude beyond which you won't hit anything. But this isn't flying the SID- if you are assigned the SID and accept it without telling ATC you can't maintain the required climb rate, you accept the required climb rates until you are en route. This means up to 4000, and then up to 5000 once past PLMTO unless you are cleared to a lower altitude.

Disagree that the gradient applies up to the top altitude of the SID. That altitude is for ATC procedures, i.e. traffic separation, rather than obstacle avoidance. The minimum IFR altitude is based on obstacles rather than traffic.

@randomhead The minimum en route altitude is also based on such things as radio communications and navigational signal availability. If not the top altitude of the departure, what other altitude could it be? It's clearly not the MOCA after PLMTO since that doesn't even provide obstacle clearance until after PLMTO. And it doesn't make sense for it to be the MEA after PLMTO since anyone doing this departure will level off below that.

Where are you getting that phrase "minimum en route altitude" which you quoted in your answer? Both the AIM and the IPH use "minimum IFR altitude." Edit: I see you're getting it from AIM 5–2–9f rather than 5–2–9e1 referenced by OP. I'd contend that the language which matches across the AIM and the IPH is the better one to look at.